Optional

A monad that allows for a class to hold a non-existing value without using the null value, which may be valid.

The Java implementation is the generic type Optional<T>.

This class internalises all the checks for null on the client behalf, by ensuring if null represents a missing value, the semantics of this missing value is preserved throughout the operation.

This is better than using the non-wrapper to represent this as a null could possibly be a valid value (instead of a missing item).